Chesapeake Bay Monitoring
"Monitoring for Management Actions"

  10.  glossary

Algal Bloom - high concentrations of phytoplankton (algae) that occur when conditions, such as light and nutrients, are sufficient to support rapid growth.

Anoxic - a condition where no oxygen is present.

Anthropogenic - of human origin.

Benthic Organisms - organisms living in or on bottom sediments in aquatic habitats.

Biomass - the quantity of living matter, expressed as a concentration of weight per unit area in aquatic systems.

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Chlorophyll - the green pigments in plant cells, such as phytoplankton, that are active in photosynthetic reactions; chlorophyll concentration is often used as a measure of phytoplankton biomass.

Deep Trough Region - the deepest portion of the Chesapeake Bay mainstem which is located from the Annapolis Bay Bridge to just below the confluence of the Potomac River. This area experiences severe oxygen depletion of bottom waters during summer.

Detritus - particulate organic matter that is freshly dead or partially decomposed.

Ecosystem - an interactive system which includes the organisms of a natural community together with their physical and chemical environment.

Estuary - semi-enclosed, tidal, coastal body of saline water with a free connection to the sea and within which sea water is measurably diluted with fresh water derived from land drainage; commonly the lower end of a river.

Euphotic Zone - the surface layer of a body of water which receives sufficient sunlight to support photosynthesis by phytoplankton or rooted aquatic vegetation.

Eutrophication - a complex response by aquatic systems to the excess input of nutrients that stimulate phytoplankton growth. The increased phytoplankton growth leads to other problems such as low dissolved oxygen and shading of submerged aquatic vegetation.

Food Web - the network of pathways within an ecosystem that link organisms to their prey and to their predators.

Hypoxic - a condition where only very low levels of oxygen are present.

Inorganic Compounds - chemical compounds generally not containing carbon and thus not classified as organic compounds; in aquatic systems, inorganic forms of nutrients such as nitrogen and phosphorus are most readily utilized by growing phytoplankton.

Metabolism - the chemical and physical processes occurring in living organisms.

Microgram (μg) - a unit of mass equal to one millionth of a gram.

Milligram (mg) - a unit of mass equal to one thousandth of a gram.

Nutrients - chemicals, primarily nitrogen and phosphorus, that are required for growth, development and reproduction of plants.

Organic Compounds - chemical compounds containing the element carbon; these compounds are the primary constituents of living matter.

Photosynthesis - the synthesis of organic compounds from water and carbon dioxide using light energy in the presence of chlorophyll.

Phytoplankton - microscopic plants (algae) suspended in the water column.

Phytoplankton Productivity - the rate at which a phytoplankton community is growing, often expressed as the generation of biomass in terms of carbon; also known as primary productivity.

Plankton - aquatic organisms, either plants or animals, that are found drifting passively or swimming weakly in the water column.

Pycnocline - the region in a water column where water density changes rapidly, usually due to changes in salinity and temperature; in the Chesapeake Bay, the pycnocline region separates fresher, surface waters with a net flow down-Bay from saltier, bottom water with a net flow up-Bay.

Recycling - as applied to aquatic nutrients, these are the cyclical pathways traveled by elements that result in chemical changes between organic and inorganic forms; these changes are often mediated by biological activity.

Sediment Oxygen Demand (SOD) - the rate at which biological and chemical reactions taking place in bottom sediments consume oxygen from the overlying water column.

Turbidity - decreased clarity of water caused by the presence of dissolved or suspended matter.

Water Column - term used to refer to a water body in its vertical extent.

Zooplankton - small, often microscopic, animals suspended in the water column.

a.    Preface
b.   Acknowledgements
1.   Introduction
2.   Understanding The Bay's Problems
3.   Program Description
4.   Chemical and Physical Properties
5.   Plankton
6.   Benthic Organisms
7.   Ecosystem Processes
8.   Pollutant Inputs
9.   Management Strategies and the Role of Monitoring
10. Glossary

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